While talking to my ortho "God" about my elbow problems, I mentioned your friend's situation. My doc's response was that PCL's are night and day different from ACL's.
He wouldn't even speculate on what might be possible without actually examining and manipulating the knee (which is kind of unusual for this particular doc because he's usually pretty willing to give me advice tidbits out of the blue). He said your friend needs to see a doc, specifically one who specializes in PCL's if at all possible.
I don't know where you or your friend live, but he said that a Dr. John Bergfeld at the Cleveland Clinic is one of the best in the country for PCL.
Also, this website has some fun info on PCL's. It doesn't exactly say what they use for a graft, but I would bet it's either a hamstring graft, a cadaver graft, or a synthetic.http://www.stoneclinic.com/pcl.htm